Binomial Coefficients

[Come BERBAIN]

Hi,

first of all, this library is GREAT! Thanks !!
I am using it to compute some large numbers and I got a problem 
the computing of binomial coefficients is to slow. 
I'm computing binomial coefficients near (n n/2) for n around 1 000 000
I saw that a lot of work can be done for binomial coeficient and i started
some of it. But there is a suggestion of  Conrad Curry 

quote begin
Conrad Curry reports a big speedup for binomial coefficients using a prime 
powering scheme, at least for k near n/2 
end quote

what exactly is this prime powering scheme?
how to use the decomposition of n to compute (n n/2)?

Thanks in advance for your answers and suggestions about this subject.

Côme BERBAIN